This invention relates to an alternative antenna arrangement for a passive entry and ignition system for a vehicle. The system uses an electronically coded card or xe2x80x98smart cardxe2x80x99 that electronically conveys identifying information to an on board antenna system. The on board antenna system, in turn, then communicates to a vehicle control unit to enable actuation of various predetermined mechanical systems of a vehicle such as the vehicle entry system or the vehicle ignition system.
Typically, such passive entry systems involve the use of at least two and up to three interiorly placed antennas for electronically receiving identifying information from an externally located smart card and communicating to the vehicle control unit. Generally, the several antennas are necessary to cover all of the possible area where the card may be carried. Often, this arrangement includes a large antenna system positioned within the vehicle. This system requires a plurality of electrical components and thus, a plurality of switching relays to occur in order to positively respond to the coded information on the smart card provided by the vehicle user at a point adjacent to, yet external from, the vehicle.
It would be desirable to provide a passive entry system for a vehicle that utilizes a simplified antenna arrangement thus requiring fewer electrical components for scanning and receiving electronic information from a smart card, while at the same time covers a larger, yet more clearly defined, scanning area of the vehicle allowing information to be recited either adjacent to or directly within the vehicle.
In a disclosed embodiment of this invention, a passive entry system for a vehicle is provided with a single antenna to scan the vehicle""s interior as well as an external area adjacent to the vehicle for identifying information which is carried by the vehicle user on an electronically coded smart card.
The antenna is integrated into a previously existing element of the vehicle""s interior such as the roof panel using conventional wire or flat cable technology. A single antenna integrated in the roof panel covers a significant and clearly defined overhead area in which electronic identifying information may be detected.
In another embodiment, a single antenna may be integrated into a previously existing occupant detection mat, thus providing a significant and clearly defined underbody area in which electronic identifying information may be detected. The integration of the antenna into the existing electronic detection mat reduces the number of separate electronic components which must be designed and incorporated into the vehicle. This is a very inexpensive location for the antenna.
These and other features of the present invention can be understood from the following specification and drawings, the following of which is a brief description.